Retractable piston actuator



Nov. 28, 1967 R. M GIRR RETRACTABLE PISTON ACTUATOR 2 Sheets-Sheet 2 Filed Oct. 14, 1965 mm mm vm mm mm R M O T i mw i M W r.. e b 0% R N hm mm mm 5 kn United States Patent OfiFice 3,354,634 Patented Nov. 28, 1967 3,354,634 RETRACTABLE PISTON ACTUATGR Robert McGirr, Orwigsburg, Pa, assignor to Atlas Chemical Industries, Inc., Wilmington, Del., a corporation of Delaware Filed Oct. 14, 1965, Ser. No. 495,993 3 Claims. (Cl. Gil-26.1)

ABSTRACT OF THE DISCLOSURE This invention relates to an actuating device and more particularly to a retractable piston actuator which is capable of producing a great pull force.

Explosive operated actuators employed heretofore in missile and satellite systems have not been generally satisfactory due to their large size, heavy weight and lack of power.

It is the object of the present invention to provide a piston actuator of small size, light weight and possessing great pull force.

In the device of the present invention the aforesaid dis advantages of prior art actuators have been eliminated. The subject actuator is noted to be of uncomplicated structure and composed of very few essential parts. Thus providing for small size, light weight and dependable action. Of particular significance is the fact that the present device utilizes only one fluid pressure seal; whereas actuators of the prior art required many more seals. Because of the unique structure involving the use of only one seal it is possible to obtain unusually high pull force for a small diameter.

The explosive piston actuator of the present invention is fluid pressure operated and comprises in combination a tubular outer housing, a tubular inner case, a piston grooved to receive a sealing means, a squib and a retaining washer.

More specifically the subject device is comprised of a tubular outer housing having an apertured end portion and an attaching means and a tubular inner case having an extension means extending through said apertured end of the outer housing. Disposed within the inner case is a piston having a face portion in sealing engagement with the inner case and an opposite portion bearing against the apertured end of the outer housing. Positioned within the forward end of the inner case is a closing means, which is spaced from the face of the piston and which provides a pressure bearing surface. Between the forward end of said piston and the closing means is positioned a fluid pressure producing means so as to permit fluid pressure to be exerted against said piston and said closing means and thereby causing retraction of the extension means of the inner case into the outer housing.

The inner case is preferably so shaped and positioned in relation to the outer housing that lateral and rotational movement within the outer housing is prevented. The inner case is constructed to permit longitudinal movement within the outer housing. The inner case when operatively positioned within the outer housing is secured against rotational sliding by means of its longitudinally slotted end projecting through two corresponding openings in the rear end of the outer housing. The slotted end protruding from the outer case may be provided with a threaded insert or other suitable connecting attachment which is welded or otherwise secured within the slotted end of the inner case and which in turn may be connected to the object to be actuated.

The advantages and improvements in the retractable piston actuator of the present invention will be apparent from the following description of the invention taken in connection with the accompanying drawings which illuse trate a specific embodiment and wherein:

FIGURE 1 is a rear end view of an embodiment of the invention.

FIGURE 2 is a broken exploded view, partially in section, of the actuator of FIG. 1.

FIGURE 3 is a cross-sectional view, taken along the line BB of FIG. 1 with component parts in'before fire position.

FIGURE 4 is a cross-sectional view, taken along the line B-B of FIG. 1 with components in after-fire position.

Referring now to the drawings in which like numerals and references are employed to designate like parts throughout the several views, numeral 11 refers to an elongated cylindrical outer housing composed of any material suitable for such purpose, for example, stainless steel or bronze. Numeral 21 refers to the inner cylindrical case which is composed of, for example, stainless steel or cupro nickel.

Referring to FIGURE 3 approximately two-thirds of the length of inner case 21 is disposed so as to fit tightly within outer housing 11 in the before-fire position and approximately one-third its length is slotted and projected through apertures 13 and 15 of the outer housing as shown in FIGURE 2.

Squib 39 as shown in FIG. 2 and FIG. 3 is positioned within the forward end of case 21. Squib 39 is composed of lead wires 29 and 29 which are connected to match 34 through bridge wire 33 and gas-forming powder charge 35. Match 34 may be comprised of any suitable material such as lead mononitroresorcinate. The powder charge 35 is encompassed by ferrule 27. Ferrule 27 may be made of any suitable material, for example, brass. Squib 39 is sealed in the forward end of the inner case by glass plug 39 having a metal periphery 32 which may be made of any suitable metal, for example, steel. Immediately adjacent the rear end of powder charge 35 is positioned the forward end of piston 23 which may be composed of any suitable material, for example bronze. The forward end of piston 23 is grooved to receive O-ring 25, which provides a tight seal within inner case 21. The O-ring may be made of any suitable material, for example, rubber. The opposite end of piston 23 is positioned against the apertured inner end wall of outer housing 11 in such manner to allow the entire slotted end of inner case 21 designated as 17 and 19 to protrude through apertures 13 and 15 of outer housing 11. The rear portion of outer housing is equipped with screw thread 12 providing for attaching the present actuator to any suitable object.

Threaded insert 41 is longitudinally welded in the slotted end of inner case 21 between slotted ends 17 and 19 as shown in FIGURES 3 and 4.

The entire inner case assembly as shown in FIG. 3 is held in the before-fire position by washer 37 placed Within outer housing 11 and immediately adjacent to the forward end of inner case 21. Retaining washer 37 can be made of any suitable material, for example, rubber or Teflon.

The forward end of inner case 21 is provided with a retaining inner lip 38 which acts to lock the squib element 39 in the forward end of inner case 21.

In the normal operations of the present piston actu- '3 0 ator electric current is brought, by means of lead wires 29 and 29' to squib 39 whereby bridge wire 33 is heated and which in turn ignites match 34. The ignition of match 34 initiates gas forming charge 35. The gases produced by charge 35 push against the forward end of the inner case assembly so as to drive the entire inner case 21 to the left or the after-fire position as shown in FIG. 2.

What is claimed is:

1. An actuating device comprising a tubular outer housing having an apertured end portion, a tubular inner case slidably mounted in said outer case, a slotted extension means attached to said inner case and extending through said apertured end, a piston in said inner case and in sliding contact therewith, said piston having a face portion in sealing engagement with said inner case and an opposite portion bearing against said apertured end of said tubular outer housing, a means closing said inner case spaced from the face of said piston and providing a pressure bearing surface opposite said piston, a fluid pressure producing means positioned in said inner case so as to permit exertion of pressure against said piston and said closing means, whereby upon such exertion of pressure said extension means is retracted into said outer housing.

2. An actuating device comprising a tubular outer housing having an apertured end and a tubular inner case which is partially slotted and slidably fitted through said apertured end of the outer housing and mounted with connecting means, a piston in said inner case having a face portion comprising outwardly extending ribs which form a groove for receiving a sealing means which is in engagement with said inner case and having an opposite end portion bearing against said pierced end of said outer housing, a means closing said inner case spaced from the face of said piston and providing a pressure bearing surface opposite said piston, a gas producing means positioned in said inner case so as to permit exertion of pressure against said piston and said closing means whereby upon such exertion of pressure the slotted portion of the inner case is retracted into said outer housing.

3. An explosive operated actuating device comprising an elongated outer housing having an apertured end and attaching means, an elongated inner case which is slotted approximately one-third its length and slidably fitted in said outer case and through said apertured end of the outer housing and mounted with connecting means, a piston in said inner case having a face portion comprising outwardly extending ribs which form a groove for receiving a sealing means which is in engagement with said inner case and having an opposite end portion hearing against said apertured end of said outer housing, a closing means and squib in said inner case spaced from the face of said piston and providing a pressure bearing surface opposite said piston, whereby upon exertion of pressure, resulting from the ignition of said squib, upon the said piston and said closing means, the slotted portion of the inner case is retracted into said outer housing.

References Cited UNITED STATES PATENTS 3,024,592 4/1962 Leaman 6026.1

SAMUEL W. ENGLE, Primary Examiner. 

3. AN EXPLOSIVE OPERATED ACTUATING DEVICE COMPRISING AN ELONGATED OUTER HOUSING HAVING AN APERTURED END AND ATTACHING MEANS, AN ELONGATED INNER CASE WHICH IS SLOTTED APPROXIMATELY ONE-THIRD ITS LENGTH AND SLIDABLY FITTED IN SAID OUTER CASE AND THROUGH SAID APERTURED END OF THE OUTER HOUSING AND MOUNTED WITH CONNECTING MEANS, A PISTON IN SAID INNER CASE HAVING A FACE PORTION COMPRISING OUTWARDLY EXTENDING RIBS WHICH FORM A GROOVE FOR RECEIVING A SEALING MEANS WHICH IS IN ENGAGEMENT WITH SAID INNER CASE AND HAVING AN OPPOSITE END PORTION BEARING 